An artificial prosthesis sphincter may be implanted into a patient for applying occlusive pressure to the urethra and restore continence in cases where the natural sphincter muscles have been surgically excised or damaged by disease or physical trauma. Implantation of artificial sphincters commonly requires major surgery, necessitating hospitalization. The procedure is complex and usually takes six to eight weeks for recovery. In most cases, the patient also faces up to two additional months of delay before the success of the surgery can be ascertained, i.e., whether the patient is continent. Because of the swollen and aggravated condition of edema of the urethral tissues during and after surgery, the physician cannot precisely match the occlusive pressure of the patient's urethra. Therefore, he must estimate the minimal occlusive pressure required to achieve continence in the individual patient. This can result in improper selection and fitting of sphincteric devices. Therefore, occlusive pressures generated by these devices may be either insufficient to successfully achieve continence or excessive to the point of affecting blood flow and causing ischemia and subsequent erosion of the urethral tissue. Additional surgery may be required if the sphincter is insufficient to hold the patient continent or if it malfunctions. Further surgery may also be required for sphincter adjustment, repair or explant.
Urinary incontinence may be successfully treated by non-surgical means with periurethral injection of polytef paste to increase localized tissue volume. This increased localized tissue volume increases external occlusive pressure to the urethra, causing a partial obstruction and, thus, continence. However, substantial migration of polytef particles from the injection site often occurs. In addition, the paste may induce tissue reaction with Teflon.RTM. granulomas. Thus, patient safety with use of the prior art devices is questionable, resulting in reduced application of this non-surgical procedure.
The assignee of the present invention is also assignee of U.S. Pat. No. 4,686,962 issued Aug. 18, 1987 entitled "Disposable Cartridge Assembly for Hypodermically Implanting a Genitourinary Prosthesis" and U.S. Pat. No. 4,832,680, issued May 23, 1989 entitled "Apparatus for Hypodermically Implanting a Genitourinary Prosthesis" the disclosures of which are hereby incorporated by reference. Briefly, the assemblies disclosed therein each include a non-surgical hypodermically implanted genitourinary prosthesis. A biocompatible fluid or suspended particulate material is injected into a single containment membrane to overcome urinary incontinence. Patient safety remains a primary concern, avoiding the toxic effects of Teflon.RTM.-based paste and the migration of particles from the injection site.